396 



NATURE STUDY AND LIFE 



these little aquaria are so convenient that they will be 

 used much oftener than the larger ones for definite 

 experiments, like germination of seeds, rearing insects, 

 feeding tests with toads, frogs, and salamanders, purifica- 

 tion of water by tadpoles, fresh-water clams, mosquito 



Fig. 159. Forms anij Sizes of Aquaria 

 J", 5 X 7 X 4, in which meal worms are i^eing reared; 2, S x 10 x 4 ; ,7, same, with 

 liytrap attacliment ; ./, 12 x 24 x 12 ; j, 8 x 10 x 4, made flat and set up for 

 toads' eggs. 



larvae, etc. They are useful at every season and easily 

 changed from one kind of work to another. 



Suppose we have decided on lo X 8 X 5, the size 

 shown in course of construction in Fig. 158, and have our 

 glass cut square to these dimensions. We go to a tin- 

 ner's and ask him for two strips of |-inch, "three-cross" 

 angle tin the length of the sheet, which is 28 inches, 

 and four pieces 10^ inches long. These should be made 



